Chuck jaw adjusting means



Dec. 15,1959

L. C. PONTING CHUCK JAW ADJUSTING MEANS Filed NOV. 6, 1958 IN VEN TOR. LEONARD C. PONTING ATTORNEY United States Patent CHUCK JAW ADJUSTING MEANS Leonard C. Punting, Pawtucket, R.I., assignor to Pratt & Whitney Company, Incorporated, West Hartford, Conn,. a corporation of Delaware Application November 6, 1958, Serial No. 772,381

3 Claims. (Cl. 279-123) This invention relates to work holding chucks and particularly to an individual jaw adjustment therefor enabling extremely fine adjustments of a work engaging jaw to be made relative to its master or operating jaw.

An object of primary importance of the invention is to provide a radial adjusting means for a work engaging jaw relative to its master or operating jaw in which all lost motion or back lash between the parts of the adjusting means will be eliminated.

A feature of the invention that enables the above object to be accomplished is that a two-part threaded member is set into a recess in one of the members of the jaw and engages partial screw threads in the other member of said jaw, the two aligned parts of the threaded member being adjustably connected together so that by simultaneously rotating both parts of the threaded member the radial position of the work engaging jaw relative to its master jaw may be adjusted; and, by relatively rotating the two aligned threaded members the total or overall length of the threaded member may be increased.

Another object of the invention is to provide operating and relative adjusting means for the components of the threaded member enabling the two components to be simultaneously rotated for adjustment purposes of the work engaging jaw and also for relatively rotating one of the components relative to the other by means of which the overall length of the two part-member may be increased to eliminate all lost motion between the threaded components and the jaw members.

And finally it is an object of the invention to provide conventional operating wrench means enabling the two components of the threaded member to be simultaneously rotated or for one of the components to be rotated relative to the other from the outer periphery of the chuck.

With the above and other objects in view the invention may include the features of construction and operation set forth in the following specification and illustrated in the accompanying drawing.

In the accompanying drawing annexed hereto and forming a part of this specification I have shown the invention embodied in a conventional lever operated chuck, but it will be understood that the invention can be otherwise embodied and that the drawing is not to be construed as defining or limiting the scope of the invention, the claims appended to this specification being relied upon for that purpose.

In the drawing:

Figure 1 is a sectional view taken through a master jaw of a chuck showing the positioning and locking members therefor;

Fig. 2 is an outer end view of the parts shown in Fig. 1 taken from the left hand side of Fig. 1;

Fig. 3 is a side elevation of the two-part wrench adapted to adjust the connecting means or for positioning them to eliminate back lash; and

Fig. 4 is an end view of the wrenches shown in Fig. 3.

In the above-mentioned drawing there has been shown but one embodiment of the invention which is now deemed preferable but it is to be understood that changes and modifications may be made within the scope of the appended claims without departing from the spirit of the invention.

The present invention represents an improvement upon the form of jaw adjusting means shown and described in the patent to Singer 346,133 granted July 27, 1886.

Referring more in detail to the figures of the drawing,

there is shown in Fig. 1 a portion of a conventional pneumatically operated chuck for the rotatable spindle of; a machine tool having a body member 10 provided with suitable radial slots 12 within which the master jaws 14' of the chuck are radially movable. But one of these jaws 14 is shown. It will be understood, however, that several of the jaws are provided movable within radiating slots of the body member 10. To effect radial movement of the master jaw 14 a bell-crank lever 16 is provided pivotally mounted within the body member 10 and having its shorter end engaging a transverse slot in the lower member of the master jaw and its longer end engaging a peripheral groove in an axially movable member 18 which may be operated by any means forming no part of the present invention.

In the operation of work holding chucks it is frequently desirable to slightly adjust a work engaging jaw 20 relative to its operating or master jaw member 25 to provide 1 the two parts14 and 25 of the master jaw. Partial screw threads 26 are formed in the upper member 14 of the operating jaw to which is clamped the work engaging jaw 20. By rotation of the threaded member therefore the work engaging jaw 20 with the upper member 14 of the operating jaw will be adjusted slightly radially 1 relative to its lower member 25 housed within the recess 12. In such constructions, however, some back lash or lost motion is required to enable the threaded member 22 to be rotated within its recess 24. Also there will be a slight amount of lost motion or back lash between the threaded portions of the jaw member and the flanks of the threads on the threaded member 22.

In order to eliminate this lost motion between the cooperating parts of this adjusting mechanism the threaded member 22 is made in two longitudinal sections. These members 22 and 28 as shown, are housed within the recess 24 in the lower member operating jaw 25 with the end faces of the aligned members 22 and 28 bearing against the opposite end faces of the recess 24. The two members 22 and 28 are adjustingly connected together at their adjacent ends so that by rotation of one of the threaded members relative to the other the overall length of the two threaded members will be increased or decreased.

The adjustable connection between members 22 and 28 may be made by interengaging threads, external threads being formed on an extension 30 formed on the member 22 entering an internally threaded recess formed within the member 28. In the increased length of these members 22 and 28 they will abut firmly against the end walls of the recess and the flanks of the screw threads on the portions of the threaded members 22 and 28 will similarly be spread apart to bear firmly against opposite portions of the threads formed on the upper member of the operating jaw 14.

In order to actuate this adjusting means a special form of wrench is provided having concentric sleeves 32 and 34. At one end of each sleeve is a non-circular wrench portion. The outer wrench 34 has its square or non-cir- Patented Dec. 15, 1959 cnlarend adapted tofit within a non-circular recess formed in the outer" end of threaded" member 28, Theinner of the two wrenches 32 has its non-circular end extending beyond the end of the outer wrench 34 as shown.- This end is adapted toenter' a non-circular recess within the threaded projection 30 on the outer end of the threaded members'22.

It will be seen from the above description that by simultaneously rotating the two wrenches 32' and 34 the two threaded members 22' and 28 will be simultaneously rotated and there will be no increase or decrease in the overall length of these two member The chuck jaw, however,- will be radially'adjusted toward orfrom the-axis of rotation of the chuck depending upon the direction of rotation of the members 22- and 28. However, one of the wrenches is" held stationary and 'theothe'r rotated; one-of-the threaded'members 22 or 28 Willbe rotated upon'it's axis and by means of the'threa'ded connection between the' two threaded members the-overall length of the two'members' will be increased or decreased.

After an adjustment ofthejaw has been made to'the' desired position of the jaw bysimultaneous rotation of the two aligned threaded members-'22 and 28, the two threaded members may be relatively rotated to increase the overall length of the aligned members; This relative rotation by movement of one wrench relative tothe other will lock thethreaded-members 22 and 28 in the recess provided therefor and also-will cause thefianks of the threads on-the alignedmembers to tightlyengage the'opposite sides of thethread flanksof the'fragmentary internal screw threads in the work engaged jaws. In this position all lost motion orba'ck'lash is eliminated and the jaw member 14'-is securely'lockedin position.

1. In achuck; the combination of' a two-member master jaw-radially adjustable in said chuck, the'mating surface of one of said jaw members having a recess formed therein; partial screw threads formed'in the mating surface of the other of said jaw members, 'a two-part 4, threaded member fitting within said recess and engaging said screw threads to adjust the position of one of said members of said master jaw relative to its other member, and an adjustable connection between the parts of said threaded member, whereby the overall length of said member may be increased to lock said threaded member withinits recess.

2. In a chuck, the combination of a two-member master jaw radially adjustable in said chuck, the" mating surface of. one of saidv jaw members having a recess formed therein, partiai screw threads formed in the mating surface of the other of. said jaw members, a twopart threaded member'fi'tting within said recess and engaging said screw threads to adjusttthe longitudinal. position of one of said members of said master jaw relative to its other memher, and a threaded connection between the parts of said threaded member, whereby by relative rotation of one of said" threaded members relative to the other the overall length of said member may be increased to lock 'said threaded member within s'aidrecess;

3. In a chuck, the combination of a twopart master jaw radially adjustable in said chuck, the mating surface of one of said jaw members having a recess formed therein, partial screw threads formed in the mating surface of the other of said jaw members, a two-part threaded member fitting within said recess and engaging said screw'threads to adjust the position of one of said members of said master jaw'relative to its other mem" ber, a threaded connection between the parts of said threaded member, and wrench-means to simultaneously rotate said threaded members and to relatively rotate one of the parts thereof relative to=the other.

References Cited in the file of this patent UNITED STATES PATENTS 346,133 Singer July 27, 1886 2,464,854 De Martin Mar. 22, 1949 2,569,056 Highb'erg Sept. 25, 1951 2,687,308 Highb'erg Aug. 24, I954 

